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    <script>
        // 2、输入月份，显示当月的天数（使用case 穿透简化代码）1-12

        var month = prompt("请输入月份") - 0
        switch (month) {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                console.log(month + '该月份有31天');
                break

            case 4:
            case 6:
            case 9:
            case 11:
                console.log(month + '该月份有30天')
                break
            case 2:
                console.log(month + '该月份有28天')
                break
            default:
                console.log('请输入1-12的月份')

        }
    </script>
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